Patent GB-1114075-A (GB)
Title: Improvements in or relating to a method and apparatus for assembling venetian blinds
Inventor: HUNTER EDWIN JAMES
IPC: E06B9/266
Filed: 1966-07-28
Abstract: 1,114,075. Venetian blind assembly machine. HUNTER DOUGLAS INTERNATIONAL Ltd., 28 July, 1966, No; 33939/66. Heading E1J. In a venetian blind assembly machine which cuts metal slats to length from a coil 56 of slat stock after passing through a forming roller system 62 and a slat stock accummulator 64, Fig. 3, the slat stock is turned at right angles between friction drive rollers 66, 67 and through two left and right hole punch dies 70, 71 and a cut-off die 72, the die 71 punching the left hand hole of a slat and the die 70 the right hand hole of the following slat, the left hand end portion of the stock being cut off simultaneously with the punching of the holes. The cut-off length is then driven by a wheel 75 onto the ladder tapes 40, attached temporarily by hooks (42, Fig. 27) to the head rail 38, Fig. 2 which hooks also spread the side tapes 48 as far apart as possible these tapes 48 passing through guides 50, Fig. 2 (Fig. 30) on the cross member 18 the hole and cut-off die mechanism being controlled by an arm linkage 242-238 of a cam follower 236 operated by a cam mechanism on shaft 146 driven from an electric motor 132, the shape of the effective cam surface 168, Fig. 14 being such as to accelerate the movement of the slat stock up to a relatively high linear velocity and then smoothly decelerating to a much lower velocity e.g. 3 ft. per second just prior to the leading end of the slat impacting a limit stop to avoid damage of the slat by the impact. The lobes of cam 168, are contoured to terminate the lift of follower 236 abruptly to its initial starting point, the cycle having consequential correspondingly varied movement of the friction drive wheel 66 through the mechanism 242, 244, 246, 248, 250. At the end of a slat operation, the head rail carrier 24 is raised an increment with increasing acceleration to a maximum and decreasing deceleration to stop, presenting the next lower cross tape of the ladders to receive the next lower slat. All the individual operational steps are brought about by cam followers controlled by appropriately shaped cams on the shaft 146 and linkages. The dies 70, 71, 72 are operated simultaneously for a two-ladder system but are modified for a blind with more than two ladders. At the end of the slat assembling operation, a bottom rail is inserted into the bottom rungs of the ladder tapes and the blind raised to an elevated position by closing switch 376, Fig. 2 to operate mot- or 112, the lifting drum 76, and is then lowered by depressing foot treadle 127 over threading needles inserted into the guides 50 and threaded with the lifting cords which are thus taken through the punched holes in the slats, the treadle 127 releasing the lifting drum 76 and allowing the carrier rail 24 to descend by gravity. The blind is raised again to clear the needles and the ends of the cords removed from the needles and secured to the bottom rail. The pay-off roll 56 is mounted on a structure 10 inclined at 15‹ from the vertical and has a shaft 58 perpendicular thereto to receive a control core of the slat stock coil so that gravity holds the coil against the structure 12. Also by means of slanting guide surfaces for the slat stock, gravity retains the stock on the guides.